abstract public class Product {
  abstract public String getName();
}

public class ConcreteProductA extends Product{
  public String getName() {
    return "ProductA";
  }
}

public class ConcreteProductB extends Product {
  public String getName() {
    return "ProductB";
  }
}

abstract public class Creator {
  abstract public Product factoryMethod();
  public void anOperation() {
    Product p = this.factoryMethod();
    System.out.println(p.getName() + "を生成しました");
  }
}

public class ConcreteCreatorA extends Creator {
  public Product factoryMethod() {
    return new ConcreteProductA();
  }
}

public class ConcreteCreatorB extends Creator {
  public Product factoryMethod() {
    return new ConcreteProductB();
  }
}

public class Client {
  public static void main(String[] args) {
    Creator a = new ConcreteCreatorA();
    a.anOperation();

    Creator b = new ConcreteCreatorB();
    b.anOperation();
  }
}

C:\JavaHello\Factory Method>java Client
ProductAを生成しました
ProductBを生成しました

C:\JavaHello\Factory Method>